5.1 Fog and Poor Visibility

5.1 Fog and Poor Visibility

Fog is one of the most significant and hazardous weather phenomena in the United Arab Emirates (UAE), particularly in the Emirate of Abu Dhabi. During the transition seasons—specifically late autumn and winter (from October to March)—the combination of high humidity from the Arabian Gulf and rapid cooling of the desert ground overnight leads to dense radiation fog. This type of fog can reduce horizontal visibility to less than 10 metres within a matter of minutes. Driving in these conditions requires a complete shift in driving behavior, adherence to dynamic regulatory systems, and strict compliance with vehicle lighting rules.

The Abu Dhabi Smart Fog Control System

To mitigate the extreme risks associated with multi-vehicle pileups during foggy conditions, the Abu Dhabi Police, in collaboration with the Department of Municipalities and Transport, operate an automated Smart Traffic Control System. This system is designed to dynamically adjust speed limits on major highways and arterial roads based on real-time visibility sensors.

When visibility drops below 120 metres, the smart overhead gantry screens (dynamic message signs) display the reduced speed limit of 80 km/h.

• Immediate Compliance: Drivers must reduce their speed to 80 km/h immediately when they see the smart screens activated.
• Speed Cameras: Speed radars along the highway are automatically re-calibrated to flash and penalize any vehicle traveling at 81 km/h or above.
• No Buffer: The default speed buffer system in Abu Dhabi (where the speed limit is the exact limit, e.g., 140 km/h on major highways, which had its buffer removed in 2018 anyway) enforces the 80 km/h limit strictly.
• Notifications: The system also distributes warnings via SMS alerts, mobile police application notifications, and radio broadcasts.
• Deactivation: The 80 km/h limit remains in place until the police officially declare that the fog has cleared and the dynamic signs return to displaying the default speed limit. Fines for violating this temporary limit are substantial and accompanied by license black points.

Safe Following Gaps in Fog

Under normal, dry, and clear driving conditions, the UAE driving curriculum teaches the two-second rule as the minimum safe following distance. On high-speed highways, this is often extended to three seconds. However, in foggy conditions, your reaction time and stopping distances are severely compromised.

In fog, you must increase your following gap to at least four to five seconds.

This increase is necessary for several reasons:

1. Reduced Perception Time: You cannot react to what you cannot see. A stationary vehicle or a crash ahead will only become visible at the very last moment.
2. Moisture on the Road: Fog deposits a fine layer of moisture on the asphalt, reducing tire friction and increasing the physical braking distance.
3. Tailgating Hazards: If a vehicle behind you is tailgating, do not accelerate. Instead, gradually reduce your speed to increase the gap in front of you. This gives you more room to brake gently if a hazard appears, preventing the tailgater from crashing into the back of your car.

Correct Headlight and Fog Light Operation

Maintaining visibility while ensuring you do not blind other drivers is a delicate balance in the fog.

Low-Beam Headlights

It is mandatory to turn on your low-beam headlights during fog. Low beams project light downwards and slightly to the right, illuminating the road surface directly in front of the vehicle.

High-Beam Headlights (The Danger of Glare)

You must never use high-beam headlights in fog. High beams project an intense, straight beam of light. When this light hits the millions of suspended water droplets that make up fog, it scatters and reflects directly back into your eyes. This creates a blinding white wall of glare, reducing your visibility to near zero and making it impossible to see the road or other vehicles.

Fog Lights

If your vehicle is equipped with front and rear fog lights, you should activate them:

• Front Fog Lights: These are mounted low on the front bumper and project a wide, flat beam of light under the fog layer.
• Rear Fog Lights: These are extremely bright red lights designed to help drivers behind you see your vehicle from a safe distance. In the UAE, rear fog lights are highly effective in preventing rear-end collisions.
• Deactivation: Remember to turn off your fog lights as soon as visibility improves to avoid dazzling or blinding other drivers under normal conditions.

The Hazard Lights Rule in Fog (CRITICAL EXAM POINT)

One of the most dangerous and common driving errors during fog in the UAE is the misuse of hazard warning lights (double indicators).

The Golden Rule: Do NOT drive with your hazard lights turned on in the fog.

Hazard lights are designed to be used under specific circumstances:

• When your vehicle is stationary due to a breakdown or accident.
• To warn following drivers of a sudden, severe hazard directly ahead (e.g., traffic coming to an abrupt halt).

If you drive with your hazard lights on in the fog, you create severe hazards:

1. Confusion of Movement: Other drivers behind you cannot tell if your vehicle is moving or completely stopped. In dense fog, this confusion frequently leads to panic braking or rear-end collisions.
2. Loss of Turn Signals: When hazard lights are flashing, your turn signals (indicators) are disabled. If you need to change lanes or turn, you cannot signal your intention to other drivers, making maneuvers extremely hazardous.
3. Visual Fatigue: The flashing yellow lights reflect off the fog, causing visual fatigue and distraction for other drivers.

What to Do If Visibility Is Too Poor to Continue

If the fog is so thick that you cannot see the road markings or the vehicle directly in front of you:

1. Do not stop on the active highway lanes. Stopping on the road in fog is a major cause of fatal chain-reaction pileups.
2. Signal and exit the highway: Use the nearest exit or pull into a petrol station or a designated rest area.
3. Use the shoulder as a last resort: If you cannot exit, pull completely onto the right shoulder, as far away from the active traffic lanes as possible.
4. Secure the vehicle: Once safely parked off the road, turn off your driving headlights (so other drivers do not follow you onto the shoulder thinking you are still on the road), leave your parking lights on, and turn ON your hazard lights to show that you are a stationary vehicle.

Defrosters and Interior Visibility

Foggy conditions outside are usually accompanied by high humidity, which causes the interior glass surfaces of your vehicle to fog up due to the temperature difference.

• Air Conditioning: Turn on the air conditioning (A/C) to dehumidify the cabin air.
• Defroster (Demister): Direct the airflow to the front and rear windscreens to clear the condensation.
• Wipers: Keep your windscreen wipers running on an appropriate speed to clear external condensation and mist.

Defensive Behaviors in Fog

• Listen: Open your windows slightly. At junctions or low-visibility stretches, listening can warn you of approaching vehicles before you can see them.
• Stay in Your Lane: Avoid unnecessary lane changes. Follow the painted road markings (lines) to stay centered in your lane.
• Patience: Never attempt to overtake slower vehicles in dense fog.